When handling papers, the tips of the fingers become dry and slippery and it is difficult to separate individual sheets of paper from each other.
In the past, this has been remedied by wetting the fingers by licking them, which is of course unsanitary and repellent to the observer.
Another solution proposed in the past has been to provide an artificial substance which increases the friction of the fingers. It is necessary to apply this substance to the fingertips from time to time; and in addition to the inconvenience of doing this, there is the drawback that the material tends to transfer to the paper, thus soiling the paper. Also, the fingers must be washed after using this material, and of course certain persons are sensitive to the material thus applied to the fingers.
A very common expedient is to use a finger cot or stall. However, these devices completely enclose the end of the finger and cause unfavorable reactions in a large number of users, even to the point of the loss of a fingernail.